Photo-alignment copolymer, photo-alignment film, and optical laminate

Abstract

A photo-alignment copolymer has a repeating unit A including a photo-alignment group represented by Formula (1), and a repeating unit B including a crosslinkable group represented by Formula (2), a photo-alignment film is formed using a photo-alignment film composition containing the photo-alignment copolymer, an optical laminate has the photo-alignment film and an optically anisotropic layer, and an image display device has the optical laminate.

What is claimed is: 
     
         1 . A photo-alignment copolymer comprising:
 a repeating unit A including a photo-alignment group represented by Formula (1); and   a repeating unit B including a crosslinkable group represented by Formula (2),   
       
         
           
           
               
               
           
         
         in Formula (1), R 1  represents a hydrogen atom or a methyl group, R 2 , R 3 , R 4 , R 5 , and R 6  each independently represent a hydrogen atom or a substituent, and among R 2 , R 3 , R 4 , R 5 , and R 6 , two adjacent groups may be bonded to form a ring, 
         in Formula (2), R 7  represents a hydrogen atom or a methyl group, 
         L 1  in Formula (1) and L 2  in Formula (2) each independently represent a divalent linking group formed by combining at least two or more groups selected from the group consisting of a linear, branched, or cyclic alkylene group having 1 to 10 carbon atoms and optionally having a substituent A, an arylene group having 6 to 12 carbon atoms and optionally having a substituent B, an ether group, a carbonyl group, and an imino group optionally having a substituent C, and 
         the substituent A is at least one substituent selected from the group consisting of a halogen atom, an alkyl group, and an alkoxy group, the substituent B is at least one substituent selected from the group consisting of a halogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a cyano group, a carbonyl group, and an alkoxycarbonyl group, and the substituent C is at least one substituent selected from the group consisting of an alkyl group and an aryl group. 
       
     
     
         2 . The photo-alignment copolymer according to  claim 1 ,
 wherein any one of L 1  in Formula (1) and L 2  in Formula (2) is a divalent linking group including a branched, or cyclic alkylene group having 3 to 10 carbon atoms and optionally having a substituent A.   
     
     
         3 . The photo-alignment copolymer according to  claim 1 ,
 wherein any one of L 1  in Formula (1) and L 2  in Formula (2) is a divalent linking group including an imino group optionally having a substituent C.   
     
     
         4 . The photo-alignment copolymer according to  claim 1 ,
 wherein L 1  in Formula (1) is a divalent linking group including any of a linear alkylene group having 1 to 10 carbon atoms and optionally having a substituent A, a cyclic alkylene group having 3 to 10 carbon atoms and optionally having a substituent A, and an arylene group having 6 to 12 carbon atoms and optionally having a substituent B.   
     
     
         5 . The photo-alignment copolymer according to  claim 4 ,
 wherein L 1  in Formula (1) is a divalent linking group including a linear alkylene group having 1 to 10 carbon atoms and optionally having a substituent A or a cyclic alkylene group having 3 to 10 carbon atoms and optionally having a substituent A.   
     
     
         6 . The photo-alignment copolymer according to  claim 5 ,
 wherein L 1  in Formula (1) is a divalent linking group including a cyclic alkylene group having 3 to 10 carbon atoms and optionally having a substituent A.   
     
     
         7 . The photo-alignment copolymer according to  claim 1 ,
 wherein L 1  in Formula (1) is a divalent linking group including a cyclic alkylene group having 3 to 10 carbon atoms and optionally having a substituent A or an imino group optionally having a substituent C, and L 2  in Formula (2) is a divalent linking group including an imino group optionally having a substituent C.   
     
     
         8 . The photo-alignment copolymer according to  claim 1 ,
 wherein at least R 4  among R 2 , R 3 , R 4 , R 5 , and R 6  in Formula (1) represents a substituent.   
     
     
         9 . The photo-alignment copolymer according to  claim 8 ,
 wherein R 2 , R 3 , R 5 , and R 6  in Formula (1) all represent a hydrogen atom.   
     
     
         10 . The photo-alignment copolymer according to  claim 1 ,
 wherein R 4  in Formula (1) is an electron-donating substituent.   
     
     
         11 . The photo-alignment copolymer according to  claim 1 ,
 wherein the substituents represented by R 2 , R 3 , R 4 , R 5 , and R 6  in Formula (1) each independently represent a halogen atom, a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, a linear halogenated alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, a cyano group, an amino group, or a group represented by Formula (3),   
       
         
           
           
               
               
           
         
         in Formula (3), * represents a bonding position with a benzene ring in Formula (1), and R 8  represents a monovalent organic group. 
       
     
     
         12 . The photo-alignment copolymer according to  claim 1 ,
 wherein a content X of the repeating unit A and a content Y of the repeating unit B satisfy Formula (4).
   0.2≤ X /( X+Y )≤0.8  (4)
 
   
     
     
         13 . The photo-alignment copolymer according to  claim 12 ,
 wherein a content X of the repeating unit A and a content Y of the repeating unit B satisfy Formula (5).
   0.2≤ X /( X+Y )≤0.6  (5)
 
   
     
     
         14 . The photo-alignment copolymer according to  claim 1 ,
 wherein a weight-average molecular weight is 10,000 to 500,000.   
     
     
         15 . The photo-alignment copolymer according to  claim 14 ,
 wherein a weight-average molecular weight is 30,000 to 200,000.   
     
     
         16 . The photo-alignment copolymer according to  claim 1 , further comprising:
 a repeating unit C represented by Formula (6),   
       
         
           
           
               
               
           
         
         in Formula (6), R 9  represents a hydrogen atom or a methyl group, 
         in Formula (6), L 3  represents a divalent linking group formed by one group or combining one or more groups selected from the group consisting of a linear, branched, or cyclic alkylene group having 1 to 10 carbon atoms and optionally having the substituent A, an arylene group having 6 to 12 carbon atoms and optionally having the substituent B, an ether group, a carbonyl group, and an imino group optionally having the substituent C, and 
         in Formula (6), Q represents any group of —OH, —COOH, and —COOtBu. 
       
     
     
         17 . A photo-alignment film which is formed using a photo-alignment film composition containing the photo-alignment copolymer according to  claim 1 . 
     
     
         18 . An optical laminate comprising:
 the photo-alignment film according to  claim 17 ; and   an optically anisotropic layer which is formed using a liquid crystal composition containing a liquid crystal compound.